The present invention relates generally to tags and seals and more particularly to a magnetic vector field tag and a magnetic vector field seal and to a method for providing an object with a magnetic vector field tag and a magnetic vector field seal.
Tags are generally used to identify and provide information relating to an object or objects, both animate and inanimate. For example, a tag can be an identification badge for a pet, a label to identify a piece of luggage, a scannable barcode to provide a manifest of items in a container, etc. Tags include cards having magnetic stripes for scanning into a reading device for credit purchases, for withdrawing cash from teller machines, for gaining access to restricted workplaces, etc.
An object can be magnetically tagged to provide it with an identifiable magnetic field signature so that it can be remotely located. For example, U.S. Pat. No. 4,940,966 to R. M. Pettigrew et al. entitled xe2x80x9cArticle Detection and/or Recognition Using Magnetic Devices,xe2x80x9d which issued Jul. 10, 1990, describes a method for magnetically tagging an object and then locating it as it moves through a pipe. Magnetic elements are attached to an object to provide the tag. The tagged object is placed into an underground pipe system. As it travels through the pipe system, it can be located using an interrogating magnetic field.
U.S. Pat. No. 5,565,847 to R. J. Gambino et al. entitled xe2x80x9cMagnetic Tag Using Acoustic or Magnetic Interrogation,xe2x80x9d which issued Oct. 15, 1996, describes a magnetic tag that includes magnetic cantilevers of various sizes and shapes. The cantilevers are attached to the object to tag it. The tagged object is exposed to an external magnetic field to induce vibrations at the resonance frequency of a cantilever. The time-varying magnetic field produced by the vibrating cantilever is detected to identify the tagged object.
While tags are used generally to identify objects, seals are used to indicate whether an object such as a container has been, or at least may have been, tampered with. Container seals provide a detectable indication that a container break in may have occurred, and that the container and/or objects stored inside may have been tampered with. For example, U.S. Pat. 5,729,199 to M. N. Cooper et al. entitled xe2x80x9cSecurity System for a Metallic Enclosure,xe2x80x9d which issued Mar. 17, 1998 describes a seal that provides an audible signal when the seal is broken. A battery operated radio-frequency transmitter unit is placed inside a metallic enclosure. The unit transmits radio signals that are detected by a receiver outside the enclosure to indicate the security status of the enclosure.
U.S. Pat. No. 3,688,256 to R. F. D""Ausilio et al. entitled xe2x80x9cVehicle Intrusion Alarm System,xe2x80x9d which issued Aug. 29, 1972, describes a seal that includes a magnet attached to a door of a vehicle and a nearby receiver that detects changes in magnetic field strength. When the door is opened the changing magnetic field strength near the door induces a voltage in the receiver to activate an alarm.
Sometimes, an intruder may wish to interrogate a container without stealing objects inside while avoiding detection. A successful intrusion defeats the seal by providing the intruder with important information while leaving the appearance that no intrusion has taken place.
Clearly, a method for generally providing an object with a tag and seal is highly desirable.
Therefore, an object of the present invention is a method of providing an object with a magnetic tag and seal.
Another object of the invention is a method for providing an object with a random magnetic field signature that provides the object with a tag and seal.
Yet another object of the invention is a method for providing a container with a magnetic tag to identify the container without having to open it.
Another object of the invention is an inexpensive and easily installable magnetic seal for a container.
Yet another object of the invention is a magnetic tag and seal that is difficult to detect.
Another object of the invention is a magnetic tag and seal that is difficult to defeat.
Another object of the invention is a magnetic tag and seal that can be monitored repeatedly without measurably altering the tag and seal.
Another object of the invention is a magnetic tag and seal for a container where the status of the tag and seal does not require constant monitoring.
Yet another object of the invention is a magnetic tag and seal for a container that does not require magnetic field generating devices external to the container.
Additional objects, advantages and novel features of the invention will be set forth in part in the description which follows, and in part will become apparent to those skilled in the art upon examination of the following or may be learned by practice of the invention. The objects and advantages of the invention may be realized and attained by means of the instrumentalities and combinations particularly pointed out in the appended claims.
To achieve the foregoing and other objects, and in accordance with the purposes of the present invention as embodied and broadly described herein, the invention includes a method for providing an object with a magnetic vector field tag and seal. The method involves placing a magnetometer at a first location near an object and placing at least one magnet at a second location near the object, the magnet providing a measurable magnetic field strength at the first location of the magnetometer. The magnetometer is then used to record the magnetic field strength and vector direction at its first location to provide the object with a magnetic vector field tag and seal. The magnetometer is then moved away from the object to a location where it cannot be detected.
The invention also includes a method of providing an object with a magnetic vector field tag and seal. The method involves positioning a magnetometer at a first location near an object and placing each magnet of a plurality of magnets at a separate location near the object, the plurality of magnets providing a measurable magnetic field strength and vector direction at first location of the magnetometer. The magnetometer is then used to record the magnetic field strength and vector direction using the magnetometer at its first location to provide the object with a magnetic vector field tag and seal. The magnetometer is then moved away from the object to a location where it cannot be detected.
The invention also includes a magnetic device having a permanent magnet and a wheel having a chamber sufficiently large for receiving the magnet and allowing it to tumble randomly inside when the wheel rotates about its axis. The device also has an axle coincident with the wheel axis about which the wheel can rotate.
The invention also includes a magnetic device having a plurality of permanent magnets and a wheel having a plurality of chambers, each chamber sufficiently large to receive at least one of the magnets and allow it to tumble randomly inside when the wheel rotates about its axis. The device also has an an axle coincident with the wheel axis about which said wheel can rotate.
The invention also includes a movable tray having a permanent magnet and at least three wheels, where one of the wheels has a chamber sufficiently large to receive the magnet and allow it to tumble randomly inside when the wheel rotates about its axis. The tray includes axles for each wheel, each axle being coincident with the wheel axis about which said wheel can rotate. The tray also includes a substantially flat support having a first side for supporting objects thereupon and a second side for attaching said wheels thereto such that the support can be rolled across a surface. The tray also includes means for attaching the wheels to the support.
The invention also includes a magnetic device having a wheel having a rotational axis, the wheel comprising a magnetic material. The device also includes an axle coincident with the rotational axis of the wheel, and a track configured to receive the wheel and allow the wheel to roll and slide therein as it moves within the track.
The invention also includes a magnetic device for providing an object with a magnetic vector field tag and seal. The device includes a permanent magnet and a support for attaching the magnet thereto. The support is flexible enough that it can be wrapped around an object to provide the object with a magnetic vector field tag and seal by placing the device around the object and recording the magnetic field strength and vector direction from at least one direction near the object.
The invention also includes a magnetic device for providing an object with a magnetic vector field tag and seal. The device includes a plurality of permanent magnets and a support for attaching said magnets thereto. The support is flexible enough that it can be wrapped around an object to provide the object with a magnetic vector field tag and seal by placing the device around the object and recording the magnetic field strength and vector direction from at least one location near the object.